U.S. patent number 10,185,070 [Application Number 15/283,789] was granted by the patent office on 2019-01-22 for display device and light source device.
This patent grant is currently assigned to Japan Display Inc.. The grantee listed for this patent is Japan Display Inc.. Invention is credited to Tsutomu Harada, Susumu Kimura, Akira Sakaigawa.
United States Patent |
10,185,070 |
Kimura , et al. |
January 22, 2019 |
Display device and light source device
Abstract
According to one embodiment, a light source device includes a
light source element including a first light emitting element which
emits light of a first wavelength and a second light emitting
element which emits light of a second wavelength, a first
wavelength conversion material which is excited by the light from
the first light emitting element to emit light of a third
wavelength, and a second wavelength conversion material which is
excited by the light from the second light emitting element to emit
light of a fourth wavelength, wherein cyan light produced by the
light emission of the first light emitting element and magenta
light produced by the light emission of the second light emitting
element are emitted from the same light emitting surface.
Inventors: |
Kimura; Susumu (Tokyo,
JP), Harada; Tsutomu (Tokyo, JP),
Sakaigawa; Akira (Tokyo, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Japan Display Inc. |
Minato-ku |
N/A |
JP |
|
|
Assignee: |
Japan Display Inc. (Minato-ku,
JP)
|
Family
ID: |
58446701 |
Appl.
No.: |
15/283,789 |
Filed: |
October 3, 2016 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20170097458 A1 |
Apr 6, 2017 |
|
Foreign Application Priority Data
|
|
|
|
|
Oct 5, 2015 [JP] |
|
|
2015-197381 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02F
1/133603 (20130101); G02B 6/0026 (20130101); G02F
1/133514 (20130101); G02F 2001/133624 (20130101); G02B
6/0068 (20130101); G02F 2001/133614 (20130101); G02B
6/0003 (20130101) |
Current International
Class: |
F21V
8/00 (20060101); G02F 1/1335 (20060101) |
Field of
Search: |
;362/608 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Tso; Laura
Attorney, Agent or Firm: Oblon, McClelland, Maier &
Neustadt, L.L.P.
Claims
What is claimed is:
1. A light source device comprising: a light source element
including a first light emitting element which emits light of a
first wavelength and a second light emitting element which emits
light of a second wavelength; the light source element including a
first wavelength conversion material which is excited by the light
from the first light emitting element to emit light of a third
wavelength and a second wavelength conversion material which is
excited by the light from the second light emitting element to emit
light of a fourth wavelength, wherein cyan light produced by the
light emission of the first light emitting element and magenta
light produced by the light emission of the second light emitting
element are emitted from the same light emitting surface, the first
light emitting element and the second light emitting element are
sealed in a single space in the light source element, the first
wavelength conversion material and the second wavelength conversion
material are mixed and sealed in the single space in the light
source element, the light from the first light emitting element and
the light from the second light emitting element are emitted from
the light emitting surface through the single space in which the
first wavelength conversion material and the second wavelength
conversion material are mixed.
2. The light source device according to claim 1, wherein the first
wavelength conversion material and the second wavelength conversion
material include a phosphor or a quantum dot.
3. The light source device according to claim 1, wherein white
light produced when both the first light emitting element and the
second light emitting element emit light at the same time is
emitted from the light emitting surface.
4. The light source device according to claim 1, wherein the light
source element includes four terminals connected to an anode and a
cathode of each of the first light emitting element and the second
light emitting element.
5. The light source device according to claim 1, wherein the light
source element includes a common terminal which electrically
connects the first light emitting element and the second light
emitting element and two terminals electrically connected to anodes
or cathodes of each of the first light emitting element and the
second light emitting element.
6. The light source device according to claim 1, wherein the second
wavelength is different from the first wavelength.
7. A display device comprising: a display panel; a light source
element including a first light emitting element which emits light
of a first wavelength and a second light emitting element which
emits light of a second wavelength; a lightguide plate including an
incident surface which is opposed to the light source element and
an exit surface which is opposed to the display panel; the light
source element including a first wavelength conversion material
which is excited by the light from the first light emitting element
to emit light of a third wavelength and a second wavelength
conversion material which is excited by the light from the second
light emitting element to emit light of a fourth wavelength,
wherein cyan light produced by the light emission of the first
light emitting element and magenta light produced by the light
emission of the second light emitting element are emitted from the
same light emitting surface to illuminate the display panel, the
first light emitting element and the second light emitting element
are sealed in a single space in the light source element, the first
wavelength conversion material and the second wavelength conversion
material are mixed and sealed in the single space in the light
source element, the light from the first light emitting element and
the light from the second light emitting element are emitted from
the light emitting surface through the single space in which the
first wavelength conversion material and the second wavelength
conversion material are mixed.
8. The display device according to claim 7, wherein the display
panel further includes a first subpixel including a yellow color
filter and a second subpixel including a blue color filter.
9. A light source device comprising: a light source element
including a first light emitting element which emits light of a
first wavelength and a second light emitting element which emits
light of a second wavelength; the light source element including a
first wavelength conversion material which is excited by the light
from the first light emitting element to emit light of a third
wavelength and a second wavelength conversion material which is
excited by the light from the second light emitting element to emit
light of a fourth wavelength, wherein light of a first color
including at least the light of the third wavelength which is
produced by the light emission of the first light emitting element
and light of a second color including at least the light of the
fourth wavelength which is produced by the light emission of the
second light emitting element are emitted from the same light
emitting surface, the first light emitting element and the second
light emitting element are sealed in a single space in the light
source element, the first wavelength conversion material and the
second wavelength conversion material are mixed and sealed in the
single space in the light source element, the light from the first
light emitting element and the light from the second light emitting
element are emitted from the light emitting surface through the
single space in which the first wavelength conversion material and
the second wavelength conversion material are mixed.
10. The light source device according to claim 9, wherein the first
wavelength conversion material and the second wavelength conversion
material include a phosphor or a quantum dot.
11. The light source device according to claim 9, wherein white
light produced when both the first light emitting element and the
second light emitting element emit light at the same time is
emitted from the light emitting surface.
12. The light source device according to claim 9, wherein the
second wavelength is different from the first wavelength.
13. The light source device according to claim 9, wherein the light
source element includes four terminals connected to an anode and a
cathode of each of the first light emitting element and the second
light emitting element.
14. The light source device according to claim 9, wherein the light
source element includes a common terminal which electrically
connects the first light emitting element and the second light
emitting element and two terminals electrically connected to anodes
or cathodes of each of the first light emitting element and the
second light emitting element.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority
from Japanese Patent Application No. 2015-197381, filed Oct. 5,
2015, the entire contents of which are incorporated herein by
reference.
FIELD
Embodiments described herein relate generally to a display device
and a light source device.
BACKGROUND
Mobile devices are commercially used. Mobile devices such as
smartphones, personal assistant devices, and tablet computers have
a highly sophisticated display function. The mobile devices can
display a color image. As a method used to display a color image,
field sequential drive is known. In this drive method, a single
frame period is divided into, for example, three periods of a red
display period, green display period, and blue display period (or
may be referred to as three fields). Corresponding to the three
fields, pixels selected for red display, pixels selected for green
display, and pixels selected for blue display are driven.
On the other hand, as a white light source applicable to display
devices such as liquid crystal display devices, there is a light
emitting device including a blue light emitting diode which emits
blue light, ultraviolet light emitting diode which emits
ultraviolet light, red phosphor which is excited by the ultraviolet
light emitted from the lower surface of the ultraviolet light
emitting diode to emit red light, and green phosphor which is
excited by the ultraviolet light emitted from the upper surface of
the ultraviolet light emitting diode. In such a light emitting
device, the blue light emitting diode and the ultraviolet light
emitting diode are electrically connected to maintain the balance
of the mixture of red light from the red phosphor, green light from
the green phosphor, and blue light from the blue light emitting
diode. In such a light emitting device which essentially emits
white light, the blue light emitting diode and the ultraviolet
light emitting diode must emit the light at the same time, and it
may cause excessive power consumption.
As another white light source, there is a light emitting device
including a red light emitting diode, green light emitting diode,
and blue light emitting diode arranged linearly, in which the light
from two or more light emitting diodes is mixed in a lightguide
plate. However, in such a device, the light does not mix
sufficiently in the proximity of the incident surface of the
lightguide plate and the color may become vague. Such vague color
will deteriorate the display quality of the display device.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing an example of the structure of
a display device LCD in a disassembled manner.
FIG. 2 shows an example of the structure of the display panel PNL
and an example of an equivalent circuit therein.
FIG. 3 is a cross-sectional view of the display panel including a
yellow subpixel and a blue subpixel.
FIG. 4 shows the structure of a light source element PC of FIG.
1.
FIG. 5 is a schematic cross-sectional view of the light source
element PC of FIG. 4.
FIG. 6 shows an example of the color of light from a light source
unit LU and arrangement of color filters.
FIG. 7 shows a relationship between the color of light from a
backlight unit BL and colors of light from color filters CFY and
CFB in a pixel.
FIG. 8 shows an example of drive of the first light emitting
element L1 and the second light emitting element L2 and the color
displayed by the display device.
FIG. 9 shows another example of color of light from the light
source unit LU and arrangement of color filters.
FIG. 10 shows another relationship between the color of light from
the backlight unit BL and colors of light from color filters CFY
and CFB in a pixel.
FIG. 11 shows another example of drive of the first light emitting
element L1 and the second light emitting element L2 and the color
displayed by the display device.
FIG. 12 is a schematic cross-sectional view of the light source
element PC of FIG. 4.
FIG. 13 shows an example of the arrangement of light source
elements PC.
FIG. 14 shows another example of the arrangement of light source
elements PC in the light source unit LU.
FIG. 15 shows another example of the structure of the present
embodiment.
FIG. 16 shows another example of the structure of the present
embodiment.
DETAILED DESCRIPTION
In general, according to one embodiment, a light source device
includes a light source element including a first light emitting
element which emits light of a first wavelength and a second light
emitting element which emits light of a second wavelength, a first
wavelength conversion material which is excited by the light from
the first light emitting element to emit light of a third
wavelength and, a second wavelength conversion material which is
excited by the light from the second light emitting element to emit
light of a fourth wavelength, wherein cyan light produced by the
light emission of the first light emitting element and magenta
light produced by the light emission of the second light emitting
element are emitted from the same light emitting surface.
According to one embodiment, a display device includes a display
panel, a light source element including a first light emitting
element which emits light of a first wavelength and a second light
emitting element which emits light of a second wavelength, a
lightguide plate including an incident surface which is opposed to
the light source element and an exit surface which is opposed to
the display panel, a first wavelength conversion material which is
excited by the light from the first light emitting element to emit
light of a third wavelength, and a second wavelength conversion
material which is excited by the light from the second light
emitting element to emit light of a fourth wavelength, wherein cyan
light produced by the light emission of the first light emitting
element and magenta light produced by the light emission of the
second light emitting element are emitted from the same light
emitting surface to illuminate the display panel.
According to one embodiment, a light source device includes a light
source element including a first light emitting element which emits
light of a first wavelength and a second light emitting element
which emits light of a second wavelength, a first wavelength
conversion material which is excited by the light from the first
light emitting element to emit light of a third wavelength, and a
second wavelength conversion material which is excited by the light
from the second light emitting element to emit light of a fourth
wavelength, wherein light of a first color including at least the
light of the third wavelength which is produced by the light
emission of the first light emitting element and light of a second
color including at least the light of the fourth wavelength which
is produced by the light emission of the second light emitting
element are emitted from the same light emitting surface.
Embodiments will be described hereinafter with reference to the
accompanying drawings. Incidentally, the disclosure is merely an
example, and proper changes within the spirit of the invention,
which are easily conceivable by a skilled person, are included in
the scope of the invention as a matter of course. In addition, in
some cases, in order to make the description clearer, the widths,
thicknesses, shapes, etc. of the respective parts are schematically
illustrated in the drawings, compared to the actual modes. However,
the schematic illustration is merely an example, and adds no
restrictions to the interpretation of the invention. Besides, in
the specification and drawings, the structural elements having
functions, which are identical or similar to the functions of the
structural elements described in connection with preceding
drawings, are denoted by like reference numerals, and an
overlapping detailed description is omitted unless necessary.
FIG. 1 is a perspective view showing an example of the structure of
a display device LCD in a disassembled manner. In this example, a
liquid crystal display device will be exemplified as the display
device LCD. Such a display device can be used in various devices
such as a smartphone, tablet, feature phone, personal computer,
television, in-car device, and game console.
The display device LCD includes, for example, a display panel PNL,
double-sided tape TP, backlight unit BL, and bezel BZ. The
backlight unit BL is disposed to be opposed to a first substrate
SUB1 of the display panel PNL. The bezel BZ accommodates the
display panel PNL and the backlight unit BL.
The display panel PNL includes a flat-panel first substrate SUB1,
flat-panel second substrate SUB2 which is opposed to the first
substrate SUB1, and liquid crystal layer (which is not shown) held
between the first substrate SUB1 and the second substrate SUB2. The
first substrate SUB1 and the second substrate SUB2 are adhered
together by a sealant (which is not shown) with a certain cell gap
formed therebetween. The liquid crystal layer is sealed within the
area defined by the first substrate SUB1, second substrate SUB2,
and the sealant. A driver IC chip and a flexible printed circuit
FPC are mounted on the first substrate SUB1 as a signal supplier
which supplies signals required to drive the display panel PNL.
The display panel PNL includes a display area DA in the area where
the first substrate SUB1 and the second substrate SUB2 are opposed
to each other. In the example depicted, a display area DA is formed
in a rectangular shape. The display panel PNL includes a
non-display area NDA of rectangular frame shape outside the display
area DA. The display panel PNL of the present embodiment is, for
example, a transparent display type which displays an image using a
transparent display function which selectively passes the light
from the backlight unit BL, or a transflective display type which
displays an image using both the transparent display function and a
reflective display function which selectively reflects external
light or auxiliary light thereon.
In the example depicted, the backlight unit BL includes an optical
sheet OS, frame FR, lightguide plate LG, light source unit LU, and
reflective sheet RS.
The optical sheet OS is light transmissive and is disposed to be
opposed to the first substrate SUB1 of the display panel PNL. The
optical sheet OS includes a diffusion sheet OSA, prism sheet OSB,
prism sheet OSC, and diffusion sheet OSD as a part of the backlight
unit BL. In the example depicted, the elements in the optical sheet
OS are formed in a rectangular shape to be opposed to the display
area DA. Note that the number of diffusion sheets and prism sheets
and the layering structure thereof in the optical sheet OS are
optional and are not limited to the example of FIG. 1.
The frame FR is disposed between the display panel PNL and the
bezel BZ. In the example depicted, the frame FR is formed in a
rectangular shape and has a rectangular opening OP in the area
opposed to the display area DA. Note that the shape of the frame FR
is optional and is not limited to the example of FIG. 1.
Furthermore, it the frame FR is structurally unnecessary, it may be
omitted.
The double-sided tape TP is disposed between the display panel PNL
and the frame FR. The double-sided tape TP adheres the display
panel PNL and the frame FR together while being opposed to the
non-display area NDA of the display panel PNL. The double-sided
tape TP is formed in a rectangular shape and is, for example,
light-shielding. Note that, if the display panel PNL and the frame
FR are fixable without the aid of double-sided tape TP, the
double-sided tape TP may be omitted.
The lightguide plate LG is disposed between the frame FR and the
bezel BZ. The lightguide plate LG is formed as a flat plate. The
lightguide plate LG includes a main surface LGA which is opposed to
the frame FR, main surface LGB which is opposite to the main
surface LGA, and side surface LGC connecting the main surfaces LGA
and LGB.
The light source unit LU is arranged along the side surface LGC of
the lightguide plate LG. The light source unit LU includes, for
example, a plurality of light source elements PC and a flexible
printed circuit LFPC on which the light source elements PC are
mounted. A light source element PC is packaged light emitting
elements which will be described later, and has an exit surface
opposed to the side surface LGC of the lightguide plate LG. In this
example, the light source elements PC are arranged along the side
surface LGC to be parallel to a short side of the lightguide plate
LG; however, they may be arranged along the side surface LGC to be
parallel to a long side of the lightguide plate LG.
The reflective sheet RS is light reflective, and is disposed
between the lightguide plate LG and bezel BZ. In the example
depicted, the reflective sheet RS is formed in a rectangular shape
and is opposed to the main surface LGB.
In the present embodiment, the light source device which
illuminates the display panel PNL is a backlight unit formed in
combination with the transmissive display panel PNL; however, it
may be a frontlight unit formed in combination with a reflective
display panel PNL. Furthermore, in the lightguide plate LG, the
side surface LGC opposed to the light source elements PC
corresponds to an incident surface and the main surface LGA opposed
to the display panel PNL corresponds to an exit surface.
FIG. 2 shows an example of the structure of the display panel PNL
and an example of the equivalent circuit therein.
The display device LCD includes an active matrix display panel PNL.
The display area DA is composed of a plurality of subpixels PX
arranged in a matrix. In the display area DA, subpixels PX arranged
in the first direction X form rows, and subpixels PX arranged in
the second direction Y form columns.
Note that, in the present application, a single subpixel PX
includes a single color filter and represents a single color. A
pixel which is a minimum unit for a color image display is a
combination of several subpixels including different color filters.
A pixel may be a combination of subpixels of yellow and blue color
filters or may be a combination of subpixels of yellow, blue, and
white color filters.
The first substrate SUB1 includes, in the display area DA, a
plurality of gate lines G (G1 to Gn) arranged in the second
direction Y, a plurality of source lines S (S1 to Sm) arranged in
the first direction X, switching elements SW electrically connected
to a gate line G and source line S in each subpixel PX, and pixel
electrodes PE electrically connected to a switching element SW in
each subpixel PX. The common electrode CE is provided with at least
one of the first substrate SUB1 and the second substrate SUB2. The
common electrode CE is provided with the entirety of the display
area DA and is formed in common with the subpixels PX. The common
electrode CE is drawn to the non-display area NDA to be connected
to a power supply unit Vcom. A constant common voltage is supplied
to the power supply unit Vcom. A storage capacitance CS is formed,
for example, between the common electrode CE and the pixel
electrode PE.
Although detailed explanation of the display device PNL is omitted,
when a display mode which uses a vertical field produced
orthoganally to the substrate main surface, namely, twisted nematic
(TN) mode, optically compensated bend (OCB) mode, and vertical
aligned (VA) mode is used, and when a display mode which uses an
inclined field with respect to the substrate main surface is used,
the pixel electrodes PE are formed on the first substrate SUB1
while the common electrode CE is formed on the second substrate
SUB2. Or, when a display mode which uses a horizontal field
produced horizontally to the substrate main surface, namely, an
in-plane switching mode (IPS) which uses a horizontal field along
the substrate main surface, or a fringe field switching (FFS) mode
which is a kind of the IPS mode is used, both the pixel electrodes
PE and the common electrode CE are formed on the first substrate
SUB1. Furthermore, the display panel PNL may be configured to
conform to a display mode of an arbitrary combination of the
vertical field, horizontal field, and inclined field.
Each gate line G is drawn outside the display area DA to be
connected to a gate driver GD. Each source line S is drawn outside
the display area DA to be connected to a source driver SD. The gate
driver GD and the source driver SD are at least partly formed on
the first substrate SUB1 to be electrically connected to a driver
IC chip CP.
The driver IC chip CP includes a controller of the gate driver GD
and the source driver SD, which functions as a signal supplier
configured to supply signals necessary for the drive of the display
panel PNL. In the example depicted, the driver IC chip CP is
mounted on the first substrate SUB1 in the non-display area NDA of
the display panel PNL.
Color filters are arranged in a regular order to correspond to the
subpixels PX. In the present embodiment, the subpixels PX in one
line have the same width in the first direction X and have the
color filters of the same color. In this example, subpixels PX
arranged in the first line between source lines S1 and S2 have the
yellow color filters. Subpixels PX arranged in the second line
between source lines S2 and S3 have the blue color filters. The
lines of yellow subpixels (first subpixels) PX and the lines of
blue subpixels (second subpixels) PX are arranged alternately.
Furthermore, a yellow color filter has a width H1 which is twice
width H2 of a blue color filter. Note that, the subpixels PX have
substantially the same length in the second direction Y. That is,
in subpixels PX, the area substantially used for the image display
is greater in the first subpixels than the second subpixels.
The light source unit LU includes a plurality of light source
elements PC on the flexible printed circuit LFPC extending in the
first direction X. The light source elements PC are periodically
arranged in line in the first direction X. A light source element
PC includes a first light emitting element L1 and a second light
emitting element L2. In each light source element PC, the first
light emitting element L1 and the second light emitting element L2
are arranged side-by-side in the first direction X, for
example.
FIG. 3 is a cross-sectional view of the display panel PNL including
a yellow subpixel and a blue subpixel. In this example, only the
main structure of the display panel driven in the FFS mode will be
explained. Hereinafter, the yellow subpixel will be referred to as
the first subpixel PX1, and the blue subpixel will be referred to
as the second subpixel PX2.
The first substrate SUB1 includes a transparent first insulating
substrate 10 which is formed of a glass substrate or a resin
substrate. The first substrate SUB1 includes, on the surface of the
first insulating substrate 10 opposed to the second substrate SUB2,
common electrode CE, pixel electrodes PE1 and PE2, first insulating
film 11, second insulating film 12, and first alignment film AL1.
The common electrode CE is formed on the first insulating film 11
extending over the first subpixel PX1 and second subpixel PX2. The
second insulating film 12 covers the common electrode CE. Note that
elements which are not depicted here such as gate lines, source
lines, and switching elements are formed between the first
insulating substrate 10 and the first insulating film 11. A pixel
electrode PE1 of the first subpixel PX1 and a pixel electrode PE2
of the second subpixel PX2 are formed on the second insulating film
12 to be opposed to the common electrode CE. Pixel electrodes PE1
and PE2 each have a slit SLA to be opposed to the common electrode
CE. Pixel electrodes PE1 and PE2 are covered with a first alignment
film AL1. The common electrode CE, and pixel electrodes PE1 and PE2
are formed of a transparent conductive material such as indium tin
oxide or indium zinc oxide. Note that, in the example of FIG. 3,
the display panel PNL of FFS mode in which pixel electrodes PE are
formed on the common electrode CE is adopted; however, no
limitation is intended thereby. The display panel PNL may be of FFS
mode in which the common electrode CE is formed on the pixel
electrodes PE. Furthermore, the present embodiment may be applied
not only to a display panel of horizontal field modes such as FFS
mode and IPS mode but also a display panel of vertical field
mode.
The second substrate SUB2 includes a transparent second insulating
substrate 20 which is formed of a glass substrate or a resin
substrate. The second substrate SUB2 includes, on the surface of
the second insulating substrate 20 opposed to the first substrate
SUB1, light-shielding layer BM, color filters CFY and CFB, overcoat
layer OC, and second alignment film AL2. The light shielding layer
BM is formed on the inner surface of the second insulating
substrate 20 to be opposed to the first substrate SUB1. The light
shielding layer BM is formed of a black resin material or a light
shielding metal material. Color filters CFY and CFB are formed on
the inner surface of the second insulating substrate 20 to partly
overlap the light shielding layer BM. Color filters CFY and CFB are
opposed to pixel electrodes PE1 and PE2, respectively, with the
liquid crystal layer LQ interposed therebetween. Color filter CFY
is a yellow color filter which is formed of a yellow resin
material. Color filter CFB is a blue color filter which is formed
of a blue resin material. The overcoat layer OC covers color
filters CFY and CFB. The overcoat layer OC is formed of a
transparent resin material. The overcoat layer OC is covered with
the second alignment film AL2. The first alignment film AL1 and the
second alignment film AL2 are formed of a material indicative of
the horizontal alignment.
The first substrate SUB1 and the second substrate SUB2 are adhered
together with a certain cell gap is formed therebetween. The liquid
crystal layer LQ is sealed between the first alignment film AL1 and
the second alignment film AL2.
A first optical element OD1 including a first polarizer PL1 is
disposed on the outer surface of the first substrate SUB1. A second
optical element OD2 including a second polarizer PL2 is disposed on
the outer surface of the second substrate SUB2.
Note that, in the example depicted, color filters CFY and CFB are
formed on the second substrate SUB2; however, they may be formed on
the first substrate SUB1. In the example depicted, color filters
CFY and CFB may be replaced with the first insulating film 11 or
may be disposed between the first insulating substrate 10 and the
first insulating film 11.
FIG. 4 shows the structure of a light source element PC of FIG.
1.
In the example depicted, a light source element PC includes the
first light emitting element L1 and the second light emitting
element L2 in a main body BX. In the example depicted, the main
body BX is formed as a rectangular parallelepiped. The light source
element PC has a single exit surface A on the side B which is
opposed to the side surface LGC of the lightguide plate LG of FIG.
1. The first light emitting element L1 and the second light
emitting element 12 are, for example, light emitting diodes. The
light emitted from each of the first light emitting element L1 and
the second light emitting element L2 exits from the exit surface
A.
Note that, in the example depicted, the light source element PC
includes two light emitting elements; however, the number of light
emitting elements may be three or more, and in either case, the
light source element PC includes a single exit surface A.
FIG. 5 shows a schematic cross-sectional view of the light source
element PC of FIG. 4. FIG. 5 shows the light source element PC,
taken along line V1-V2 of FIG. 4.
The light source element PC includes a transparent resin RE which
accommodates a lead frame LF, first light emitting element L1,
second light emitting element L2, first wavelength conversion
material EM1, and second wavelength conversion material EM2. In the
example depicted, the light source element PC further includes four
terminals T1 to T4.
The first light emitting element L1 is electrically connected to
terminals T1 and T2 through wire WR1. The second light emitting
element L2 is electrically connected to terminals T3 and T4 through
wire WR2. Terminals T1 and T2 are electrically connected to the
anode and cathode of the first light emitting element L1,
respectively. Terminals T3 and T4 are electrically connected to the
anode and cathode of the second light emitting element L2,
respectively. Terminals T1 to T4 of each light source element PC
are connected to four buslines formed on the flexible printed
circuit LFPC of FIG. 1. Thus, the first light emitting element L1
and the second light emitting element L2 emit light separately in
the light source element PC.
The first light emitting element L1 emits light of a first
wavelength. The second light emitting element L2 emits light of a
second wavelength. Note that, in this example, the first and second
wavelengths are different wavelengths. In this example, the first
and second wavelengths are the blue and ultraviolet wavelengths,
respectively. Furthermore, the first and second wavelengths may be
the same wavelength. In that case, both the first and second
wavelengths may be the blue or ultraviolet wavelengths.
The first wavelength conversion material EM1 is excited by the
light of the first wavelength emitted from the first light emitting
element L1 to emit light of a third wavelength. The second
wavelength conversion material EM2 is excited by the light of the
second wavelength emitted from the second light emitting element L2
to emit light of a fourth wavelength which is different from the
third wavelength. The first wavelength conversion materials EM1 and
the second wavelength conversion materials EM2 are included in
resin RE and are sealed in the light source element PC. The resin
RE is a transparent resin material such as epoxy or silicone. The
resin RE including the first wavelength conversion materials EM1
and the second wavelength conversion materials EM2 fills a space
between the exit surface A and the first light emitting element L1
and second light emitting element L2. Thus, when the first light
emitting element L1 emits light, the first wavelength conversion
materials EM1 not only those are opposed to the first light
emitting element L1 but also those are opposed to the second light
emitting element L2 are excited, and light of a first color
including at least the light of the third wavelength is emitted
from the entirety of the exit surface A. Similarly, when the second
light emitting element L2 emits light, the second wavelength
conversion materials EM2 not only those are opposed to the second
light emitting element L2 but also those are opposed to the first
light emitting element L1 are excited, and light of a second color
including at least the light of the fourth wavelength is emitted
from the entirety of the exit surface A. That is, the light source
element PC emits the light of the first color and the light of the
second color from the exit surface A which is the same light
emitting surface.
Both the third and fourth wavelengths are longer than the first and
second wavelengths. In this example, the third and fourth
wavelengths are the green and red wavelengths, respectively. Both
the first wavelength conversion materials EM1 and the second
wavelength conversion material EM2 are formed of, for example, a
phosphor. For example, if a red phosphor is used as a wavelength
conversion material which emits light of red wavelength, such a red
phosphor may be composed of one or more phosphor groups such as
M.sub.2O.sub.2S:Eu (where M is one or more elements selected from
La, Gd, and Y); 0.5MgF.sub.2.3.5MgO.GeO.sub.2:Mn; YO.sub.3:Eu;
Y(P,V)O.sub.4:Eu; and YVO.sub.4:Eu.
If a green phosphor is used as a wavelength conversion material
which emits light of green wavelength, such a green phosphor may be
composed of one or more phosphor groups such as
RMg.sub.2AL.sub.16O.sub.27:Eu, Mn (where R is either one or both of
Sr and Ba); RMgAl.sub.10O.sub.17:Eu, Mn (where R is either one or
both of Sr and Ba); ZnS:Cu; SrAl.sub.2O.sub.4:Eu;
SrAl.sub.2O.sub.4:Eu, Dy; ZnO:Zn; Zn.sub.2Ge.sub.2O.sub.4:Mn;
Zn.sub.2SiO.sub.4:Mn; Q.sub.3MgSi.sub.2O.sub.8:Eu, Mn (where Q is
one or more elements selected from Sr, Ba, and Ca).
Note that the first wavelength conversion material EM1 and the
second wavelength conversion material EM2 may be formed of a
quantum dot. Furthermore, in addition to the first wavelength
conversion materials EM1 and the second wavelength conversion
materials EM2, the light source element PC may include third
wavelength conversion materials for emitting light of fifth
wavelength which is different from the third wavelength and fourth
wavelength.
In the present embodiment, the light source element PC produces,
for example, cyan light as a first color when the first light
emitting element L1 and magenta light as a second color when the
second light emitting element L2. Furthermore, the light source
element PC may produce white light when the first light emitting
element L1 and the second light emitting element L2 emit light at
the same time. Such white light is emitted from the exit surface A
which is a light emitting surface. Note that a combination of the
first and second colors is not limited to the above example.
Furthermore, the first and second colors may be produced as a
combination of light emitted from a light emitting element and
light emitted from wavelength conversion materials, or as a
combination of light of different colors emitted from different
wavelength conversion materials.
FIG. 6 shows an example of the color of light from the light source
unit LU and the arrangement of color filters. In FIG. 6, some
structures such as source lines in the first substrate SUB1 side
are omitted for the sake of easier understanding of the arrangement
of color filters.
Blue color filters having width H2 and yellow color filters having
width H1 are arranged alternately in the first direction X. The
display device of the present embodiment adopts the field
sequential drive. In the example of FIG. 6, the light source units
LU emit cyan light as a first color when the first light emitting
elements L1 emit light and emit magenta light as a second color
when the second light emitting elements L2 emit light. In this
drive technique, each first light emitting element L1 turns on in
the first half of a single frame and turns off in the other half of
the frame. On the other hand, each second light emitting element L2
turns off in the first half of a single frame and turns on in the
other half of the frame.
As shown in FIG. 1, the light source elements PC are arranged
parallel to a short side of the lightguide plate LG. The light from
the light source elements PC enters the lightguide plate LG and the
light exiting the lightguide plate LG passes the light transmissive
pixels. Thus, in the field sequential drive of the display device
of the present embodiment, the emission of cyan light and magenta
light is repeated periodically.
FIG. 7 shows a relationship between the color of light emitted from
the backlight unit BL and the colors of the light from the color
filters CFY and CFB in a pixel. In the example depicted, a frame
period for the color image display includes two fields of a cyan
field Cy and a magenta field Ma. The cyan field Cy and the magenta
field Ma each correspond to a half frame period.
The backlight unit BL emits cyan light in the cyan field Cy and
magenta light in the magenta field Ma. In the cyan field Cy, the
first subpixel PX1 including a yellow color filter CFY displays
green, and the second subpixel PX2 including a blue color filter
CFB displays blue. In the magenta field Ma, the first subpixel PX1
displays red, and the second subpixel PX2 displays blue. That is,
blue can be displayed in both the cyan field Cy and the magenta
field Ma, red can be displayed in the magenta field Ma, and green
can be displayed in the cyan field Cy. Therefore, the intensity of
blue tends to be stronger as compared to the intensity of red and
green.
In the present embodiment, the area of the first subpixels PX1 with
yellow color filters is formed greater than the area of the second
subpixels PX2 with blue color filters. With this structure, the
intensities of blue, green, and red are made substantially equal in
a frame period.
Note that, to obtain a good white balance, the intensities of blue,
green, and red may not necessarily be made even. The intensities of
blue, green, and red, or the area of each of the first subpixel PX1
and the second subpixel PX2 should be designed in consideration of
the characteristics of each color filter such as transmissivity and
hue to obtain a desired white balance on a chromaticity
diagram.
FIG. 8 shows an example of drive of the first light emitting
element L1 and the second light emitting element L2, and color
displayed by the display device.
In the cyan field Cy, the first light emitting element L1 is turned
on and the second light emitting element L2 is turned off. Thereby,
the backlight unit BL emits cyan light. At that time, the light
passing through the color filter CFY becomes green light G1 and the
light passing through the color filter CFB becomes blue light B1.
In the example depicted, the intensity of blue light B1 is made
approximately half the intensity of green light G1.
In magenta field Ma, the second light emitting element L2 is turned
on and the first light emitting element L1 is turned off. Thereby,
the backlight unit BL emits magenta light. At that time, the light
passing through the color filter CFY becomes red light R2 and the
light passing through the color filter CFB becomes blue light B2.
In the example depicted, the intensity of blue light B2 is made
approximately half the intensity of red light R2.
That is, in a single frame period, each of blue light B1, blue
light B2, green light G1, and red light R2 can be recognized.
In the above example, one frame period includes two fields. Now, an
example in which one frame period includes three fields will be
explained.
FIG. 9 shows an example of the color of light from the light source
unit LU and the arrangement of color filters. As compared to the
example of FIG. 6, the light source unit LU emits cyan light, white
light, and magenta light periodically in a single frame in the
example of FIG. 9. That is, the light source unit LU emits cyan
light when the first light emitting element L1 emits light, and
magenta light when the second light emitting element L2 emits
light, and white light when the first light emitting element L1 and
the second light emitting element L2 at the same time.
FIG. 10 shows a relationship between the color of light emitted
from the backlight unit BL and the colors of the light from the
color filters CFY and CFB in a pixel. In the example depicted, a
frame period for the color image display includes three fields: a
cyan field Cy, a white field W, and a magenta field Ma. The cyan
field Cy, white field W, and magenta field Ma each correspond to a
one-third frame period.
The backlight unit BL emits cyan light in the cyan field Cy, white
light in the white field W, and magenta light in the magenta field
Ma. In the cyan field Cy, the first subpixel PX1 including a yellow
color filter CFY displays green, and the second subpixel PX2
including a blue color filter CFB displays blue. In the white field
W, the first subpixel PX1 displays yellow of a mixture of red and
green, and the second subpixel PX2 displays blue. In the magenta
field Ma, the first subpixel PX1 displays red, and the second
subpixel PX2 displays blue. That is, blue can be displayed in all
of the cyan field Cy, white field W, and magenta field Ma; red can
be displayed in the white field W and magenta field Ma; and green
can be displayed in the white field W and cyan field Cy. As in the
example of FIG. 7, the area of the first subpixels PX1 with yellow
color filters is formed greater than the area of the second
subpixels PX2 with blue color filters, and thus, the intensities of
blue, green, and red are made substantially equal in a frame
period.
FIG. 11 shows another example of the drive of the first light
emitting element L1 and the second light emitting element L2 and
the color displayed by the display device. The first light emitting
element L1 is, for example, driven to be turned on in the first
two-thirds of a frame and to be turned off in the latter one-third.
On the other hand, the second light emitting element L2 is driven
to be turned off in the first one-third of a frame and to be turned
on in the latter two-thirds.
In the cyan field Cy, the first light emitting element L1 is turned
on and the second light emitting element L2 is turned off. Thereby,
the backlight unit EL emits cyan light. At that time, the light
passing through the color filter CFY becomes green light G1 and the
light passing through the color filter CFB becomes blue light B1.
In the example depicted, the intensity of blue light B1 is made
approximately half the intensity of green light G1.
In the white field W, the first light emitting element L1 and the
second light emitting element L2 are both turned on. Thereby, the
backlight unit BL emits white light. At that time, the light
passing through the color filter CFY becomes green light G2 and red
light R2 and the light passing through the color filter CFB becomes
blue light B2. In the example depicted, the intensities of the blue
light B2, green light G2, and red light R2 become substantially
equal.
In the magenta field Ma, the second light emitting element L2 is
turned on and the first light emitting element L1 is turned off.
Thereby, the backlight unit BL emits magenta light. At that time,
the light passing through the color filter CFY becomes red light R3
and the light passing through the color filter CFB becomes blue
light B3. In the example depicted, the intensity of blue light B3
is made approximately half the intensity of red light R3.
That is, in a single frame period, each of blue light B1, B2, and
B3, green light G1 and G2, and red light R2 and R3 can be
recognized.
In the above examples, a frame period includes two or three fields,
and in some cases, a frame period may include four or more fields.
Furthermore, a combination of colors of three fields is not limited
to the above example.
In the present embodiment, a light source element PC includes a
first light emitting element L1 and a second light emitting element
L2, and first wavelength conversion materials EM1 and second
wavelength conversion materials EM2, where cyan light produced when
the first light emitting element L1 emits light and magenta light
produced when the second light emitting element L2 emits light are
emitted from the same light emitting surface (in the above example,
from the exit surface A of the light source element PC). Therefore,
as compared to a case where a spot light source of cyan and a spot
light source of magenta are provided separately, cyan light and
magenta light can be mixed in the position closer to the light
source element PC, and uneven mixture of colors can be
prevented.
Furthermore, uneven mixture of colors can be prevented in the
proximity of the incident surface (in the above example, the side
surface LGC) of the lightguide plate LG opposed to the light source
elements PC. Thus, the area in the proximity of the incident
surface of the lightguide plate LG can be used as an effective area
for illuminating the display panel PNL. Furthermore, by placing the
effective area opposed to the display area DA of the display panel
PNL, uneven mixture of colors in the display area DA can be
prevented and the deterioration in the display quality can be
prevented, too.
Furthermore, the light source elements PC can be disposed in the
proximity of the lightguide plate without causing uneven mixture of
colors. Therefore, light from the light source elements PC can be
efficiently guided into the lightguide plate LG, and the efficiency
of the light use can be improved. Furthermore, a gap between the
light source elements PC and the lightguide plate LG can be
reduced, and the display device can be manufactured with a thinner
bezel structure.
Furthermore, in the present embodiment, the field sequential drive
is adopted to illuminate the display panel PNL. Thus, one light
emitting element of a light source element is turned on in the cyan
field and the other light emitting element of the light source
element is turned on in the magenta field. In other words, two
light emitting elements of the light source element are not
constantly turned on in a single frame period. Therefore, the power
for drive can be reduced.
Now, a variation of the present embodiment will be explained.
FIG. 12 is another schematic cross-sectional view of the light
source element PC of FIG. 4. As compared to the example of FIG. 5,
the light source element PC includes three terminals T11 to T13 as
compared to the example of FIG. 12.
The first light emitting element L1 is electrically connected to
terminals T11 and T12 through wire WR1. The second light emitting
element L2 is electrically connected to terminals T11 and T13
through wire WR2. Terminal T11 is a single common terminal which
electrically connects the first light emitting element L1 and the
second light emitting element L2. In this example, terminal T11 is
electrically connected to the anode of each of the first light
emitting element L1 and the second light emitting element L2.
Terminal T12 is electrically connected to the cathode of the first
light emitting element L1, and terminal T13 is electrically
connected to the cathode of the second light emitting element L2.
Note that terminal T11 may be electrically connected to the cathode
of each of the first light emitting element L1 and the second light
emitting element L2, and in that case, terminals T12 and T13 are
electrically connected to the anodes of the first light emitting
element L1 and the second light emitting element L2,
respectively.
In this variation, as in the above example, the first light
emitting element L1 and the second light emitting element L2 emit
light separately. In addition to this point, as compared to the
example of FIG. 5 in which the light source element PC includes
four terminals, the number of buslines formed on the flexible
printed circuit LFPC can be reduced to three. Thus, the size of the
flexible printed circuit LFPC can be reduced.
FIG. 13 shows an example of the arrangement of light source
elements PC. In this example, a third direction Z is orthogonal to
both the first direction X and the second direction Y.
Light source elements PC are mounted in line on the flexible
printed circuit in the first direction X. The exit surface A of
each light source element PC is formed in a rectangle whose long
sides extend in the first direction X. In each light source element
PC, the first light emitting element L1 and the second light
emitting element L2 are arranged side-by-side in the first
direction X. The number of light source elements PC mounted on the
flexible printed circuit LFPC and the gap between the light source
elements PC can be determined arbitrarily based on the desired
intensity of light.
The first light emitting elements L1 in the light source elements
PC are connected in series. Furthermore, the second light emitting
elements L2 in the light source elements PC are connected in
series. That is, the light emitting diodes of the same color are
lit at the same time.
FIG. 14 shows another example of the arrangement of the light
source elements PC in the light source unit LU. As compared to the
example of FIG. 13, the first light emitting elements L1 and the
second light emitting elements L2 of the light source elements PC
are arranged in the third direction Z in the example of FIG.
14.
In this arrangement, the first light emitting elements L1 emit
light at the same position in the X-Y plane and the second light
emitting elements L2 emit light at the same position in the X-Y
plane. Thus, uneven mixture of colors of the first light emitting
elements L1 and the second light emitting elements L2 can be
further suppressed.
FIG. 15 shows another example of the structure of the present
embodiment. In the example of FIG. 15, the display device LCD
includes a light source element PC, lightguide plate LG, sheet SH,
and display panel PNL. The light source element PC includes an exit
surface A which is opposed to the side surface (incident surface)
LGC of the lightguide plate LG. The display panel PNL is opposed to
the main surface (exit surface) LGA of the lightguide plate LG. The
sheet SH is disposed between the lightguide plate LG and the
display panel PNL.
As in the above example, each light source element PC includes the
first light emitting element L1 and the second light emitting
element L2. The light from the first light emitting element L1 and
the second light emitting element L2 is emitted from the exit
surface A of the light source element PC. Note that, in this
example, the light source element PC does not include first
wavelength conversion materials or second wavelength conversion
materials which are included in the light source element PC of the
above embodiment. Instead, first wavelength conversion materials
EM1 and second wavelength conversion materials EM2 are sealed in
the sheet SH.
The light of the first wavelength emitted from the first light
emitting element L1 exits the exit surface A of the light source
element PC, passes the lightguide plate LG, and reaches the sheet
SH to excite the first wavelength conversion materials EM1 therein.
Thus, the light of the first color (such as cyan) including at
least the light of the third wavelength is emitted from the sheet
SH when the first light emitting element L1 emits light. The light
of the second wavelength from the second light emitting element L2
exits the exit surface A of the light source element PC, passes the
lightguide plate LG, and reaches the sheet SH to excite the second
wavelength conversion materials EM2 therein. Thus, the light of the
second color (such as magenta) including at least the light of the
fourth wavelength is emitted from the sheet SH when the second
light emitting element L2 emits light. The light of the first color
and the light of the second color are emitted from the same light
emitting surface. In the example depicted, the light emitting
surface is the main surface SHA of the sheet SH, which is opposed
to the display panel PNL.
The advantages described in the above examples can be achieved in
this example, too. Note that, the sheet SH may be replaced with any
one in the optical sheet OS of FIG. 1. That is, the first
wavelength conversion materials EM1 and the second wavelength
conversion materials EM2 may be sealed in one component of the
optical sheet OS. In that case, the number of items can be reduced,
and the thickness of the display device LCD can be decreased.
FIG. 16 shows another example of the structure of the present
embodiment. As compared to the example of FIG. 15, the sheet SH is
disposed in a different position in the example of FIG. 16. As in
the example of FIG. 15, the sheet SH includes the first wavelength
conversion materials EM1 and second wavelength conversion materials
EM2. In the example depicted, the sheet SH is interposed between
the light source element PC and the lightguide plate LG.
The advantages described in the above examples can be achieved in
this example, too. In addition, as compared to the example of FIG.
15, the size of the sheet SH can further be reduced.
As can be understood from the above, embodiments of the present
application can provide a display device and a light source device
which can achieve less power consumption and less deterioration in
display quality.
While certain embodiments have been described, these embodiments
have been presented by way of example only, and are not intended to
limit the scope of the inventions. Indeed, the novel embodiments
described herein may be embodied in a variety of other forms;
furthermore, various omissions, substitutions and changes in the
form of the embodiments described herein may be made without
departing from the spirit of the inventions. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
inventions.
Some examples of the light source device and the display device of
the present embodiment will be noted here.
(1) A light source device comprising:
a light source element including a first light emitting element
which emits light of a first wavelength and a second light emitting
element which emits light of a second wavelength;
a first wavelength conversion material which is excited by the
light from the first light emitting element to emit light of a
third wavelength; and
a second wavelength conversion material which is excited by the
light from the second light emitting element to emit light of a
fourth wavelength, wherein
cyan light produced by the light emission of the first light
emitting element and magenta light produced by the light emission
of the second light emitting element are emitted from the same
light emitting surface.
(2) The light source device according to (1), wherein the light
source element includes the first wavelength conversion material
and the second wavelength conversion material, and the light
emitting surface is formed on an exit surface of the light source
element.
(3) The light source device according to (1), comprising a sheet
including the first wavelength conversion material and the second
wavelength conversion material, wherein the light emitting surface
is formed on a main surface of the sheet.
(4) The light source device according to (1), wherein the first
wavelength conversion material and the second wavelength conversion
material include a phosphor or a quantum dot.
(5) The light source device according to (1), wherein white light
produced when both the first light emitting element and the second
light emitting element emit light at the same time is emitted from
the light emitting surface.
(6) The light source device according to (1), wherein the light
source element includes four terminals connected to an anode and a
cathode of each of the first light emitting element and the second
light emitting element.
(7) The light source device according to (1), wherein the light
source element includes a common terminal which electrically
connects the first light emitting element and the second light
emitting element and two terminals electrically connected to anodes
or cathodes of each of the first light emitting element and the
second light emitting element.
(8) The light source device according to (1), wherein the second
wavelength is different from the first wavelength.
(9) A display device comprising:
a display panel;
a light source element including a first light emitting element
which emits light of a first wavelength and a second light emitting
element which emits light of a second wavelength;
a lightguide plate including an incident surface which is opposed
to the light source element and an exit surface which is opposed to
the display panel;
a first wavelength conversion material which is excited by the
light from the first light emitting element to emit light of a
third wavelength; and
a second wavelength conversion material which is excited by the
light from the second light emitting element to emit light of a
fourth wavelength, wherein
cyan light produced by the light emission of the first light
emitting element and magenta light produced by the light emission
of the second light emitting element are emitted from the same
light emitting surface to illuminate the display panel.
(10) The display device according to (9), wherein the light source
element includes the first wavelength conversion material and the
second wavelength conversion material, and
the light emitting surface is formed on the exit surface of the
light source element.
(11) The display device according to (9), comprising a sheet
including the first wavelength conversion material and the second
wavelength conversion material, and
the light emitting surface is formed on a main surface of the
sheet.
(12) The display device according to (11), wherein the sheet is
disposed between the display panel and the lightguide plate.
(13) The display device according to (11), wherein the sheet is
disposed between the light source element and the lightguide
plate.
(14) The display device according to (9), wherein the display panel
further includes a first subpixel including a yellow color filter
and a second subpixel including a blue color filter.
(15) A light source device comprising:
a light source element including a first light emitting element
which emits light of a first wavelength and a second light emitting
element which emits light of a second wavelength;
a first wavelength conversion material which is excited by the
light from the first light emitting element to emit light of a
third wavelength; and
a second wavelength conversion material which is excited by the
light from the second light emitting element to emit light of a
fourth wavelength, wherein
light of a first color including at least the light of the third
wavelength which is produced by the light emission of the first
light emitting element and light of a second color including at
least the light of the fourth wavelength which is produced by the
light emission of the second light emitting element are emitted
from the same light emitting surface.
(16) The light source device according to (15), wherein the light
source element includes the first wavelength conversion material
and the second wavelength conversion material, and
the light emitting surface is formed on an exit surface of the
light source element.
(17) The light source device according to (15), comprising a sheet
including the first wavelength conversion material and the second
wavelength conversion material are sealed, wherein
the light emitting surface is formed on a main surface of the
sheet.
(18) The light source device according to (15), wherein the first
wavelength conversion material and the second wavelength conversion
material include a phosphor or a quantum dot.
(19) The light source device according to (15), wherein white light
produced when both the first light emitting element and the second
light emitting element emit light at the same time is emitted from
the light emitting surface.
(20) The light source device according to (15), wherein the second
wavelength is different from the first wavelength.
(21) The light source device according to (15), wherein the light
source element includes four terminals connected to an anode and a
cathode of each of the first light emitting element and the second
light emitting element.
(22) The light source device according to (15), wherein the light
source element includes a common terminal which electrically
connects the first light emitting element and the second light
emitting element and two terminals electrically connected to anodes
or cathodes of each of the first light emitting element and the
second light emitting element.
* * * * *